Valve for rock drills



July 22,1930. E. B. LEA R VALVE FOR ROCK DBILLS Filed July 19; 1928 In a INVENTOR. .E'azqLB-Leau mg g H L5 A l ORNEY.

10 weight.

Patented July 22, 1930 UNITED STATES ATENT OFFICE EARL B. LEAR, OEPHILLILPSBURG, nnw annsnv, AssIe-noR T INGERSOLL-RAND com- 'PANY, or JERSEY oIrY; NEW annsnx, A conrone'rxon on new JERSEY VALVE non noox DRILLS Application filed July- 19,

This invention relates to'rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

The objectsof the invention are to obtain a maximum piston speed, to reduce the area of'contact' between the valve and its chamher to a minimum, and to obtain avalve of simple construction possessing the desirable quality Other objects will appear hereinafter. In the drawings illustrating a practical applicationof the invention and in which similar reference characters refer to similar parts, Figure 1 isa sectional elevation of a rock drill having the invention applied thereto and showing the valve in one limiting position,

Figure 2is a similar view showing the valve in another limitingpositiomand Figure 3 is a transverse view taken through Figure 1 on the line 3-3 looking in the direction indicated by the arrows.

Referring to the drawings, the invention isshown embodied 111a rock drill having a cylinder A in which jis'disposed a reciproca'tory hammer piston B. The cylinder A is provided with a free exhaust port G preferably intermediate its ends and is controlled only by the piston B. A bushing D forms a closure for the front endof the cylinder A and in this instance also acts asa guide for a working implement E, only the shank of which is shown extending into the front end 40 bore H for'the reception of the valve chest parts comprising in this instance a central plate J and forward'andrearward plates K andL respectively. The depth of the bore H is preferably suchthat when the hood G' is screwed toits'proper assembled position of durability coupled with minimum 1928; Serial 1%.} 294,026.

on the cylinder A, the parts comprising the valve chest willbe clamped securely between the shoulder Oin the bore Hand the rearward end of the cylinder A.

Althoughthe clamping effect produced by the hood G in the cylinder A may suflfice to maintain the plates comprising the valve chest in theirproper assembled relationship with respect to each other, other suitable and well known means may-be provided for further insuring the proper assembly of the I valve chest plates J K and L. In the present disk-like plate adapted to reciprocate in the valve chamber Q. At the front and rearward ends of the valve chamber Q, are annular in- "let chambers and T respectively and from th'einletchamber S leads an inlet passage U which communicates at its opposite end with the rearward end of the cylinder A. Similarly an inlet passage V leads from the inlet chamber T to the front end of the cylinder.

Pressure fluid forj actuating the piston B may be conveyed from a source of supply (not shown) through a passage W in the hood G intoa reservoir X in the rearward end of the bore H. Such "pressure fluid is conveyed to theends of the valve chamber Q, througha supply passage Y in the plate L and a supply passage Z in the plates J, K and L leading from the reservoir X to the front end of the valve chamberQ. The outlet openings of the supply passages Y and Z in this instance are coaxial with the valve chamber Q and concentric with respect to the inlet chambers S and T; Y

In the plates K and L and encircling the inlet chambers S and T are supply chambers b and c in constant communication in this instance with the pressure fluid supply through passages (Z and e, the passage cl opening into the supply passage Z and the passage 6 opening into the reservoir X. It will thus be seen that both the supply passages and the supply chambers are in constant communication with the pressure fluid supply and therefore pressure fluid is constantly being supplied to both ends of the valve R.

Due to this construction there will at all times be an ample supply of pressure fluid to the ends of the cylinder and the valve R will be suitably balanced to prevent its tilting in the valve chamber Q. Moreover, owing to the manner in whiclr the various chambers and passages are arranged in the ends of the valve chamber only narrow annular seating surfaces f and 9 will be formed on the opposing ends of the plates K and L to act as stops for the valve R, thus reducing contact between the valve R- and the plates K and L to a minimum.

In the operation of the device, with the valve and the piston in the positions illustrated in Figure 1 pressure fluid will flow from the reservoir X into the supply chambers b and 0 and the supply passages Y and Z. With the piston in the rearward position illustrated the rearward inlet chamber T will of course be exposed to atmospheric pressure, thus causing a pressure differential which will tend to hold the valve R in its rearward position against the plate L. In this position of the valve pressure will flow from both the supply chamber 6 and from the supply passage Z into the inlet chamber S and thence through the inlet passage U into the rearward end of the cylinder to impel the piston B forwardly against the working implement E.

After the piston B covers the free exhaust port C the air in the front end of the cylinder will be compressed. Such compression flowing through the inlet passage V into the inlet chamber T will act against the rearward surface of the valve and, together with the live pressure fluid, will tend to throw the valve R forwardly against the plate K. This movement of the valve will occur immediately after the piston B overruns the exhaust port C so that at about the time the piston B strikes the working implement E a supply of pressure fluid will flow to the front end of the cylinder to return the piston to its initial position.

During the rearward travel of the piston the exhaust port C will be covered thereby and the air compressed by the piston will then flow into the inlet chamber S to act against an area of the front end of the valve equal to the area of the inlet chamber S. As the piston B proceeds rearwardly the free exhaust port C will be uncovered thereby, thus causing an abrupt drop in pressure over the rearward surface of the valve. As a consequence the live pressure fluid together with the compression acting against the front end of the valve will throw the valve rearwardly to its initial position, thus completing the cycle of operations.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder having a free exhaust port and a hammer piston in the cylinder controlling the exhaust port, a valve chest having a valve chamber, inlet passages leading from the ends of the valve chamber to the ends of the cylinder, concentric supply chambers at each end of the valve chamber and in constant communication with a source of pressure fluid supply, and a valve in the valve chamber controlling communication between the supply chambers and the inlet passages and preventing communication through the valve chamber between the supply chambers at the opposite ends thereof.

2. In a fluid actuated rock drill, the combination of a cylinder having a free exhaust port and a hammer piston in the cylinder controlling the exhaust port, a valve chest having a valve chamber, annular inlet chambers in the ends of the valve chamber, inlet passages leading from the inlet chambers to the ends of the cylinder, a plurality of supply chambers in each end of the valve chest concentric with respect to each other and with the annular inlet chambers, said supply chambers being in constant communication with a source of pressure fluid supply, and a disk valve in the valve chamber controlling communication between the inlet chambers and the supply chambers, said valve preventing the passage of fluid between the supply chambers in the opposite ends of the valve chest through said valve and said valve chamber.

3. In a fluid actuated rock drill, the combination of a cylinder having a free exhaust port and a piston in the cylinder controlling the exhaust port, a valve chest having a valve chamber, annular inlet chambers in the ends of the valve chamber, inlet passages leading from the inlet chambers to the ends of the cylinder, supply passages opening into the ends of the valve chamber and coaxial therewith, supply chambers encircling the inlet chambers, said supply passages and supply chambers being in constant communication with a source of pressure fluid supply, and a disk valve in the valve chamber for controlling the the admission of pressure from the supply passages and the supply chambers into the inlet chambers.

4. In a fluid actuated rock drill, the combination of a cylinder having a free exhaust port and a hammer piston in the cylinder controlling the exhaust port, a valve chest specification.

EARLB. LEAR. 

